It’s a qualitative difference in investment when the phone you were already going to buy shoots video at quality settings that basically can’t be beat in the same form factor. Cameras of similar size and weight can’t compete with the quality, and cameras of similar quality can’t compete with the size and weight (or price).

It’ll occupy a particular market, even if it won’t cover all of them. The $4000, 3 lb (1.3 kg) mirrorless+lens kit isn’t going to compete with the $1000 iPhone in every space, and there will be a use for high quality (but not the top professional quality) at reasonable price and accessibility.

It already captures the quality. Might as well build on board the ability to transfer full quality video at reasonable speeds.